Malaria is a widespread infectious disease leading to a million deaths annually. Human infections are caused by a protozoan parasite from the genus Plasmodium often resulting in debilitating illness commonly treated using drug-based therapies. However, an increase in drug resistant strains of Plasmodium has led to the need for new methods of treatment. Transmission blocking vaccines have been designed against antigens expressed during the lifecycle of the parasite. For use as vaccines, Plasmodium transmission blocking antigens need to be expressed at very large amounts and for a fraction of the cost of traditional vaccine proteins. The present invention demonstrates the use of algae as a suitable platform for the low cost, large-scale production of malarial vaccines. Fragments of three illustrative Plasmodium falciparum (Pfs) antigens were expressed: Pfs25, Pfs28, Pfs48/45, in the eukaryotic algal expression host Chlamydomonas reinhardtii. Animal studies have shown that immunization with these antigens results in the production of antibodies capable of blocking the transmission of malaria. Also, the bioproduction of this protein in common production hosts is difficult and often results in poor expression levels. The present invention is based, in part, on the generation of transgenic C. reinhardtii chloroplasts transformed with codon-optimized versions of the pfs25, pfs28, and pfs48/45 genes. The identities of these proteins have been confirmed using mass spectrometry proteomics. The production of immunogenic Plasmodium proteins in algae allows for the development of a cost effective transmission blocking vaccine to facilitate the eradication of malaria.